The Torcian Chronicles: Defiance by P. J. Reed

Mesham sits dejectedly in a tiny garret above an inn, as the lands of Torcia fall to the magically-enhanced army of the infamous Mivirian Horde. One of the last surviving ancient warlocks of Torcia, Mesham knows he is marked for death.

The Torcian king knocks on Mesham’s door later that evening and offers him the chance of rejuvenation in return for a seemingly impossible mission into the heart of Mivir. Mesham reluctantly agrees, only to realise the evil of Mivir has spread to the very top of the Torcian government.

As Mesham undertakes his quest to complete the mission, he finds himself hunted by his king, by the mighty Torcian warbands, and by the Horde.

But he cannot fail, for the fate of Mesham’s beloved Torcia rests in his hands.

RT @glass_poetry I know I might be the worst at this, but since it's the two thousand and eighteenth year of the common era, can we eliminate from our lexicons the phrase "shameless self promotion"?
You did the thing. You should be proud and you should, without shame, promote the hell out of it.